The Mercedes driver was speaking after Monza, where he was heavily criticized by many of his peers for his attacking defense during a duel with Lewis Hamilton.
Button had a ring-side view of the battle between his McLaren teammate and Schumacher.
"He was moving across to the left and then to the right, which I don't think was all that bright," said Briton Button, according to the Sun.
"One move (is allowed). Maybe he has just lost his memory," Button said of the 42-year-old German.
Schumacher, however, might not have heard Button's barbed comments when he was asked about the skills of the British driver.
"Even if maybe he is two per cent below the level of his peak, he (Button) is still a phenomenal talent," said Schumacher, according to SID news agency.
"He can fight for the world championship again in the right car," he reportedly told the fashion magazine Vogue.